Chernobyl (HBO Mini Series)
Discussion
ruggedscotty said:
I found it fascinating reading on the investigations, then they started to think that they did indeed have a partial nuclear explosion. more of a fizzle than a bonafide one but it was the start of one and the forces of the explosion breaking it apart before it took hold.
That's not how nuclear reactors work. The idea that they are barely-contained bombs is just a popular trope / myth and has no grounding in reality.It's actually extremely difficult, and takes a load of very specific conditions, to design and detonate a nuclear bomb and get a corresponding explosion. Those conditions simply cannot be met under any circumstances in a reactor.
Edited by Clockwork Cupcake on Saturday 4th January 14:16
https://en.wikipedia.org/wiki/Chernobyl_disaster#F...
Fizzled nuclear explosion hypothesis
The force of the second explosion and the ratio of xenon radioisotopes released after the accident (a vital tool in nuclear forensics) indicated to Yuri V. Dubasov in a 2009 publication (suggested before him by Checherov in 1998),[citation needed] that the second explosion could have been a nuclear power transient resulting from core material melting in the absence of its water coolant and moderator. Dubasov argues that the reactor did not simply undergo a runaway delayed-supercritical exponential increase in power into the multi-gigawatt power range. That permitted a dangerous "positive feedback" runaway condition, given the lack of passive nuclear safety stops, such as Doppler broadening, when power levels began to increase above the commercial level.[55]
The evidence for this hypothesis originates at Cherepovets, Vologda Oblast, Russia, 1000 km northeast of Chernobyl. Physicists from the V.G. Khlopin Radium Institute in Leningrad measured anomalous xenon-135 — a short half-life isotope — levels at Cherepovets four days after the explosion, even as the general distribution was spreading the radiation to the north in Scandinavia. It is thought that a nuclear event in the reactor may have raised xenon to higher levels in the atmosphere than the later fire did, which moved the xenon to that location.[56]
That while this positive-feedback power excursion, which increased until the reactor disassembled itself by means of its internal energy and external steam explosions,[4] is the more accepted explanation for the cause of the explosions, Dubasov argues instead that a runaway prompt criticality occurred, with the internal physics being more similar to the explosion of a fizzled nuclear weapon, and that this failed/fizzle event produced the second explosion.[55]
This nuclear fizzle hypothesis, then mostly defended by Dubasov, was examined further in 2017 by retired physicist Lars-Erik De Geer in an analysis that puts the hypothesized fizzle event as the more probable cause of the first explosion.[57][58][59] The more energetic second explosion, which produced the majority of the damage, has been estimated by Dubasov in 2009 as equivalent to 40 billion joules of energy, the equivalent of about 10 tons of TNT. Both the 2009 and 2017 analyses argue that the nuclear fizzle event, whether producing the second or first explosion, consisted of a prompt chain reaction (as opposed to the consensus delayed neutron mediated chain-reaction) that was limited to a small portion of the reactor core, since expected self-disassembly occurs rapidly in fizzle events.[55][57][60]
Lars-Eric De Geer comments:
"We believe that thermal neutron mediated nuclear explosions at the bottom of a number of fuel channels in the reactor caused a jet of debris to shoot upwards through the refuelling tubes. This jet then rammed the tubes' 350kg plugs, continued through the roof and travelled into the atmosphere to altitudes of 2.5-3km where the weather conditions provided a route to Cherepovets. The steam explosion which ruptured the reactor vessel occurred some 2.7 seconds later."[56]
Fizzled nuclear explosion hypothesis
The force of the second explosion and the ratio of xenon radioisotopes released after the accident (a vital tool in nuclear forensics) indicated to Yuri V. Dubasov in a 2009 publication (suggested before him by Checherov in 1998),[citation needed] that the second explosion could have been a nuclear power transient resulting from core material melting in the absence of its water coolant and moderator. Dubasov argues that the reactor did not simply undergo a runaway delayed-supercritical exponential increase in power into the multi-gigawatt power range. That permitted a dangerous "positive feedback" runaway condition, given the lack of passive nuclear safety stops, such as Doppler broadening, when power levels began to increase above the commercial level.[55]
The evidence for this hypothesis originates at Cherepovets, Vologda Oblast, Russia, 1000 km northeast of Chernobyl. Physicists from the V.G. Khlopin Radium Institute in Leningrad measured anomalous xenon-135 — a short half-life isotope — levels at Cherepovets four days after the explosion, even as the general distribution was spreading the radiation to the north in Scandinavia. It is thought that a nuclear event in the reactor may have raised xenon to higher levels in the atmosphere than the later fire did, which moved the xenon to that location.[56]
That while this positive-feedback power excursion, which increased until the reactor disassembled itself by means of its internal energy and external steam explosions,[4] is the more accepted explanation for the cause of the explosions, Dubasov argues instead that a runaway prompt criticality occurred, with the internal physics being more similar to the explosion of a fizzled nuclear weapon, and that this failed/fizzle event produced the second explosion.[55]
This nuclear fizzle hypothesis, then mostly defended by Dubasov, was examined further in 2017 by retired physicist Lars-Erik De Geer in an analysis that puts the hypothesized fizzle event as the more probable cause of the first explosion.[57][58][59] The more energetic second explosion, which produced the majority of the damage, has been estimated by Dubasov in 2009 as equivalent to 40 billion joules of energy, the equivalent of about 10 tons of TNT. Both the 2009 and 2017 analyses argue that the nuclear fizzle event, whether producing the second or first explosion, consisted of a prompt chain reaction (as opposed to the consensus delayed neutron mediated chain-reaction) that was limited to a small portion of the reactor core, since expected self-disassembly occurs rapidly in fizzle events.[55][57][60]
Lars-Eric De Geer comments:
"We believe that thermal neutron mediated nuclear explosions at the bottom of a number of fuel channels in the reactor caused a jet of debris to shoot upwards through the refuelling tubes. This jet then rammed the tubes' 350kg plugs, continued through the roof and travelled into the atmosphere to altitudes of 2.5-3km where the weather conditions provided a route to Cherepovets. The steam explosion which ruptured the reactor vessel occurred some 2.7 seconds later."[56]
ruggedscotty said:
No matter how you cast it, it went bang !I do think it was a prompt critical excursion, but thats by the by. He commanded his operators to operate the reactor outside of its permitted safe envelope and it went bang. The design allowing an over moderated assembly and graphite tipped control rods ultimately 'caused' the explosion, but the operating standards were unforgivable.
I watched the refuelling of an RBMK once, (had to hide in the little room up the stairs from the pile cap, because the machine did not provide sufficient shielding). The operator did not once look at any operating instructions. In the main control room, the supervisor proudly displayed their neat cabinet of pristine manuals and watching a simulator exercise, not only did the operators not read any instruction, they did not even talk to each other !
Each individual was very knowledgeable but the culture (this was in 2005) was still very 'C&C' rather than the procedure and verify methods we use.
I suppose though I must ask myself, if we had built an RBMK, could we have ever got into the same state ? In the current operating regime, not a chance. In the past ?, certainly not while I have been operating reactors.
I would like to think we would never have built anything so badly designed, but its hard to ignore the Windscale fire.
Well worth watching this chaps videos on the impact in Belarus: https://www.youtube.com/channel/UCxDZs_ltFFvn0FDHT...
The rest of his stuff is excellent too!
The rest of his stuff is excellent too!
I think people are only open mouthed if they know little of the disaster, I have always been interested in it and have watched numerous documentaries about it, so found the series awful, gave up after a few episodes, for me, it should have been a docu drama with less actors, I found it hard to watch, and as usual too character based.
I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
ceesvdelst said:
I think people are only open mouthed if they know little of the disaster, I have always been interested in it and have watched numerous documentaries about it, so found the series awful, gave up after a few episodes, for me, it should have been a docu drama with less actors, I found it hard to watch, and as usual too character based.
I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
Wow, top patronising post there. No need to apologise buddy - I couldn't give a toss whether you liked it or not I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
ceesvdelst said:
I think people are only open mouthed if they know little of the disaster, I have always been interested in it and have watched numerous documentaries about it, so found the series awful, gave up after a few episodes, for me, it should have been a docu drama with less actors, I found it hard to watch, and as usual too character based.
I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
LolI get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
As someone who knows more than the basic facts (though not as a theoretical physicist), actually does the job as a nuclear operations engineer and is authorised as a Duly Authorised Person and an Emergency Controller under a UK ONR site licence in a UK power plant and has spent time with operators on an RBMK in Russia as part of a Uk Government Department of Trade and Industry assist visit (i'm actually classed by uk government as a 'nuclear operations expert' !)...
I found it very watchable and very touching. The way it describes the basic reactor dynamics is actually very clever and while there are some calculation inaccuracies, some were real ones made at the time.
I must say though, there is the bit in the BBC drama when the explosion occurs and the operator puts his hand to his face in sheer terror, THAT sends real shivers down my spine just thinking of it. I felt that was actually done a little bit more realistically in the way the operators talked and acted.
ceesvdelst said:
I think people are only open mouthed if they know little of the disaster, I have always been interested in it and have watched numerous documentaries about it, so found the series awful, gave up after a few episodes, for me, it should have been a docu drama with less actors, I found it hard to watch, and as usual too character based.
I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
I am one of those who know a little more than the basic facts and I can't agree with you; please don't group people together with your opinions - as a person you didn't like it, that's fair enough, but I liked it and knew quite a lot about after a few years in the nuclear industry.I get why people like it, but for those of us who know the basic facts, understand what happened, I found it simply unwatchable sorry.
Fun fact...
The director of the series (Johan Renck) is aka Stakka Bo, who had a hit with the song "Here we go"
https://youtu.be/sGNK-cOtxSs
The director of the series (Johan Renck) is aka Stakka Bo, who had a hit with the song "Here we go"
https://youtu.be/sGNK-cOtxSs
98elise said:
Fun fact...
The director of the series (Johan Renck) is aka Stakka Bo, who had a hit with the song "Here we go"
https://youtu.be/sGNK-cOtxSs
Good god, that brings back some memories. Remember loving that song on Ray Cokes MTV Europes Most Wanted.The director of the series (Johan Renck) is aka Stakka Bo, who had a hit with the song "Here we go"
https://youtu.be/sGNK-cOtxSs
Talented lad to go on and make something as good as Chernobyl.
Been watching a lot of old films on YouTube.
Found this. Absolutely fascinating and very good fo seeing exactly how quick water turns to steam and and if contained what would happen.
Open water tank with a reactor in it. They increasingly remove the control rod a fraction to see what happens. In milliseconds the water is ejected at very low reactivity increase.
At 4% total destruction. Remember this was an open tank. Makes it clear to me how in a closed system like Chernobyl how powerful and quick that explosion could happen.
https://www.youtube.com/watch?v=8WfNzJVxVz4
Found this. Absolutely fascinating and very good fo seeing exactly how quick water turns to steam and and if contained what would happen.
Open water tank with a reactor in it. They increasingly remove the control rod a fraction to see what happens. In milliseconds the water is ejected at very low reactivity increase.
At 4% total destruction. Remember this was an open tank. Makes it clear to me how in a closed system like Chernobyl how powerful and quick that explosion could happen.
https://www.youtube.com/watch?v=8WfNzJVxVz4
Wildfires 'edge closer to Chernobyl nuclear plant' https://www.bbc.co.uk/news/world-europe-52274242
And when they say closer, they mean within a couple of miles
And when they say closer, they mean within a couple of miles
LaurasOtherHalf said:
And when they say closer, they mean within a couple of miles
Try less than a mile away. 
BBC News said:
The NGO's Russia branch, quoted by Reuters, said the largest fire covered 34,000 hectares, while a second fire just a kilometre from the former plant was 12,000 hectares in area.
Someone really doesn't want me to go there, cancelled our hotels and tours for next month and just waiting for Ryanair to cancel the flights 
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